Process for making chlorophosphanes, phosphinic acid chlorides or thiophosphinic acid chloride, and novel isomeric mixture consisting of chloro-phosphabicyclononanes

ABSTRACT

The disclosure relates to a process for making chlorophosphanes from primary or secondary phosphanes, or phosphinic acid chlorides or thiophosphinic acid chlorides from secondary phosphane oxides or sulfides, wherein the respective starting materials are reacted with hexachloroethane at temperatures of 20 DEG  to 180 DEG  C. The disclosure also provides as a novel chemical substance an isomeric mixture consisting of 9-Cl-9-phosphabicyclononane [3.3.1] and 9-Cl-9-phosphabicyclononane [4.2.1].

The present invention relates to a process for making chlorophosphanesof the general formula ##STR1## from primary or secondary phosphanes ofthe general formula ##STR2## or phosphinic acid chlorides orthiophosphonic acid chlorides of the general formula ##STR3## fromsecondry phoshane oxides or sulfides of the general formula ##STR4## inwhich formulae

R¹ stands for a linear or branched alkyl group, a substituted orunsubstituted aryl or cycloalkyl group having from 1 to 16 carbon atoms,preferably 1 to 8 carbon atoms,

R² has one of the meanings given for R¹ or stands for hydrogen,

R¹ and R² are --CH-bridge members of a bicyclic ring system consistingof 4 to 6 carbon atoms,

R³ has one of the meanings given for R¹,

X stands for R¹ or chlorine, and

Y stands for sulfur or oxygen.

The invention also relates to a novel chemical substance which is anisomeric mixture consisting of 9-Cl-9-phosphabicyclononane [3.3.1] and9-Cl-9-phosphabicyclononane [4.2.1].

Attempts have already been made to produce primary and secondaryphosphane halides with the use of chlorine by subjecting organicphosphanes which have two replaceable hydrogen atoms and are directlylinked to trivalent phosphorus (cf. U.S. Pat. Nos. 2,437,796 and2,437,798) to a chlorination reaction.

As the results of these tests were not reproducible, preference has beengiven to the use of phosgene as a chlorinating agent (cf. E. Steiniger,Chem. Ber. 96, 3184 [1963] and U.S. Pat. No. 3,074,994 and BritishSpecification GB-PS 904 086).

Adverse effects which are associated with this method reside in thehazardous use of very toxic phosgene and in the frequentlyunsatisfactory yields.

It has now unexpectedly been found that these adverse effects can beobviated in the process of this invention by reacting the startingmaterials with hexachloroethane at a temperature of 20° to 180° C.,preferably 80° to 120° C. It is more particularly advantageous to effectthe reaction in the presence of a solvent which should conveniently beselected from linear or branched aliphatic hydrocarbons having more than5 carbon atoms, methylcyclohexane or aromatic hydrocarbons, such asbenzene, toluene or xylenes. The present process avoids operation withtoxic phosgene. In addition to this, the chlorination effected withhexachloroethane could not be found to involve further oxidation of theresulting chlorophosphanes to give phosphonium compounds of the type [R¹R³ P⁺ Cl₂ ]Cl⁻ and [R¹ P⁺ Cl₃ ]Cl⁻, respectively.

Under the conditions selected in accordance with this invention, it ispossible to produce primary and secondary chlorophosphanes and alsophosphinic acid or thiophosphinic acid chlorides from secondaryphosphane oxides (phosphane sufides). As compared with the processesused heretofore, wherein secondary phosphane oxides are chlorinated withPCl₅ or SOCl₂ or secondary phosphane sulfide are reacted with CCl₄ inthe presence of triethylamine, the present invention provides analternative chlorination route.

The present process also permits the novel isomeric mixture referred tohereinabove which is a suitable intermediate used in makingpharmaceutical preparations and pesticides to be very reliably produced.

The melting point of this mixture of isomeric9-Cl-9-phosphabicyclononane [3.3.1] and 9-Cl-9-phosphabicyclononane[4.2.1] is 92°-96° C. and the boiling point is 120°-125° C. at 10⁻² mmHg.

The following examples illustrate the process of this invention which isnaturally not limited thereto.

EXAMPLE 1 Preparation of dicyclohexylchlorophosphane

19.8 g (0.1 mol) dicyclohexylphosphane was added dropwise at roomtemperature to 26.1 g (0.11 mol) hexachloroethane. After the exothermalreaction which took place with evolution of HCl was terminated, thereaction mixture was stirred for 3 hours at 100° C. The yields (³¹-P-NMR) were as follows: δ P=125.2 ((C₆ H₁₁)₂ PCl, 94 wgt %); δ P=194.4(C₆ H₁₁ PCl₂, 2 wgt %); δ P=76.7 ((C₆ H₁₁)₂ P(O)Cl, 4 wgt %). The crudeproduct was distilled and 13.7 g (59 wgt %) dicyclohexylchlorophosphane(bp.: 136°-138° C./4 millibars) was obtained.

EXAMPLE 2 Preparation of monocyclohexyldichlorophosphane

250 g (1.05 mol) C₂ Cl₆ was dissolved in 100 ml toluene while heating to120° C. Next, 58 g (0.5 mol) C₆ H₁₁ PH₂ was added dropwise, thetemperature of the reaction mixture being maintained at 120°-130° C. Thewhole was allowed to undergo post-reaction over 2 hours, low boilerswere removed at room temperature under vacuum and the residue wasdistilled under vacuum (δP=195; C₆ H₁₁ PCl₂, 96 wgt%). The yield was69.8 g (75 wgt %), bp=41°-42° C. under a pressure of less than 1millibar.

EXAMPLE 3 Preparation of dicyclohexylphosphonic acid chloride

A solution of 53 g (0.25 mol) dicyclohexylphosphane oxide in 150 mltoluene was added dropwise within 3 hours to a solution of 60 g (0.25mol) C₂ Cl₆ in 60 ml toluene. The temperature of the reaction mixturewas at 120°-130° C. 1 hour after gas ceased to be evolved, all volatilematter was removed at 50° C. under vacuum and the residue wasrecrystallized from hot benzene.

Yield: 18.7 g=30 wgt %; bp: 105° C., δ P=79.7 (C₆ D₆). Analysis:calculated P=12.5 wgt %, found P=12.5 wgt %.

EXAMPLE 4 Preparation of dicyclohexylthiophosphinic acid chloride

A mixture of 46.4 g dicycyclohexylphosphane sulfide and 47.4 ghexachloroethane was heated for 6 hours to 140° C. Formedtetrachloroethane was removed under vacuum and 51 g (96 wgt %) crudeproduct ((C₆ H₁₁)₂ P(:S)Cl, δ P=119.1, 99 wgt %) was retained. It wasrecrystallized from toluene. Yield: 43 g=81 wgt %, melting point=89°-90°C.

Examples 5 to 9 are summarized in the following Table:

                                      TABLE                                       __________________________________________________________________________                                        Reaction                                     Compound reacted with  React     Period                                    Ex.                                                                              hexachloroethane                                                                            Reaction product                                                                       temp. °C.                                                                   Solvent                                                                            (h)  Yield (.sup.31 P-NMR                 __________________________________________________________________________    5  9-H--phosphabicyclononane                                                                   9-Cl--phosphabi-                                                                       95-120                                                                             toluene                                                                            3    δP = 134                          isomer mixture (3.3.1)                                                                      cyclononane, iso-               99 wgt %                        and (4.2.1)   mer mixture             δP = 88                        6  t-butylphosphane                                                                            t-butyldichloro-                                                                       60-120                                                                             toluene                                                                            5    δP = 199,                                                                       48 wgt %                     7  dioctylphosphane                                                                            dioctylchloro-                                                                           100                                                                              toluene                                                                            4    δP = 112,                                                                       82 wgt %                                      phosphane                                                    8  phenylphosphane                                                                             phenyldichloro-                                                                          150                                                                              --   5    δP = 161,                                                                       74 wgt %                                      phosphane                                                    9  di-n-octylphosphine                                                                         di-n-octylchloro-                                                                      90-120                                                                             toluene                                                                            4    δP = 54,                                                                        70 wgt %                        oxide         phosphinic acid                                              __________________________________________________________________________

We claim:
 1. A process for making chlorophosphanes of the generalformula ##STR5## from primary or secondary phosphanes of the generalformula ##STR6## or phosphinic acid chlorides of thiophosphinic acidchlorides of the general formula ##STR7## from secondary phosphaneoxides or sulfides of the general formula ##STR8## in which formulae R¹stands for a linear or branched alkyl group, an aryl or cycloalkyl grouphaving from 1 to 16 carbon atoms,R² has one of the meanings given for R¹or stands for hydrogen, R¹ and R² are CH-bridge members of a bicyclicring system which includes the P atom, the two said CH-bridge members,and an additional 4 to 6 carbon atoms, R³ has one of the meanings givenfor R¹, X stands for R¹ or chlorine, and X can be R² when R² is nothydrogen, and Y stands for sulfur or oxygen, which comprises reactingthe respective starting materials with hexachloroethane at temperaturesof 20° to 180° C.
 2. The process as claimed in claim 1, wherein thereaction is carried out at temperatures of 80° to 120° C.
 3. The processas claimed in claim 1, wherein the reaction is carried out in thepresence of a solvent.
 4. The process as claimed in claim 3, wherein alinear or branched aliphatic hydrocarbon having more than 5 carbonatoms, methylcyclohexane or an aromatic hydrocarbon is used as thesolvent.
 5. The process as claimed in claim 4, wherein benzene, tolueneor a xylene is used.
 6. A process as claimed in claim 1, wherein theresulting chlorophosphane has the formula ##STR9## and is obtained froma secondary phosphanes of the formula ##STR10## wherein R¹ and R² areCH-bridge members of a phosphabicyclononane.
 7. A process as claimed inclaim 1, wherein the resulting chlorophosphane has the formula ##STR11##and is obtained from a secondary phosphane of the formula ##STR12##wherein R¹ and R² are ##STR13## bridge members of a bicyclic ring systemof the type ##STR14## wherein m=n=3 or m=2 and n=4.